\documentclass{article}
\usepackage{tikz,amsmath}
\usetikzlibrary{arrows.meta}
\usepackage[graphics,tightpage,active]{preview}
\PreviewEnvironment{tikzpicture}
\begin{document}
\begin{tikzpicture}[>=Stealth]
    \draw [semithick] (-1.5, 0) node [anchor=east] {$A$} -- (1.5, 0) node [anchor=west] {$B$};
    \draw [semithick] (0, -1.5) node [anchor=north] {$D$} -- (0, 1.5) node [anchor=south] {$C$};
    \draw (0, 0.3) -- (0.3, 0.3) -- (0.3, 0);
    \node [anchor=north east] at (0, 0) {$O$};
\end{tikzpicture}
\end{document}
